A variety of cable cutter systems for the purpose of cutting a cable or line. For example, U.S. Pat. No. 745,526 illustrates an early rope cutter system for cutting ropes used in Artesian well diggings. In U.S. Pat. No. 745,526, a weighted cutter housing is guided along the rope until reaching the rope's end socket whereupon a circular cutting edge cuts through the portion of the rope extending between a single aperture forming the guide and the centrally positioned rope end socket.
U.S. Pat. Nos. 3,320,669, 3,763,738 and 4,493,240 are illustrations of more recent explosive line cutting devices. U.S. Pat. No. 3,320,669 features a line cutting device for cutting control lines on parachutes when the supported load is expected to descend on a body of water. U.S. Pat. No. 3,320,669 includes a housing with end caps bolted thereto. The reference also includes a piston with a large diametered base, a sloping intermediate portion and a smaller diametered cylindrical projection. The housing includes a pair of opposing elongated slots through which the parachute line extends. Upon detonation of a charge forward of the base, the piston is driven such that the cylindrical projection cuts through the line and the shoulder portion of the piston contacts the intermediate portion of the passageway formed in the housing to stop piston movement. The chamber in which the base section travels includes a first radial vent and a second vent positioned further downstream just forward of the intermediate passageway. The first vent is for the exhausting of pyrotechnic gases and the second vent is for venting compressed gas in front of the piston's base section as it moves in the chamber.
U.S. Pat. No. 3,763,738 features a deep water explosive cutting tool which includes a yoke-like housing through which cables extend. The yoke includes guides for a spade-like cutter having a cylindrical rod received within a passageway formed in an outer housing. A charge is received within a bore formed at the free end of the cylindrical rod. Radial ports are provided behind a sealing ring surrounding the cylindrical rod so as to allow water to be introduced both in front of and behind the cutter for equalizing the high pressure experienced in the deep water environment.
U.S. Pat. No. 4,493,240 illustrates another explosive parachute line cutting device having a housing with a pair of diametrically opposed circular holes formed at one end through which a parachute line extends. An explosive charge system is positioned behind a blade with a circular cutting edge. At the end of the housing is positioned an annular anvil with a central aperture. The blade is forced forward so as to cut the parachute line and subsequently is stopped upon contacting the anvil. In this position, the blade's base is positioned forward of the holes and a large, unsealed chamber is provided rearward of the charge to allow for detonated gas exhaust.
An explosive cable cutter assembly designed for use with a towed aerial target is shown in U.S. Pat. Nos. 4,718,320 and 4,852,455. U.S. Pat. No. 4,852,455 shows a chisel-shaped cutter while U.S. Pat. No. 4,718,320 shows a clamping-type cutter assembly.
FIG. 12 of the present invention illustrates a previous embodiment utilized in pre-existing aerial gunnery target systems (e.g. AGTS Tow Reel, A/A 37U-36). The system shown in FIG. 12 features axially aligned elongated slots which provide for some play in the cable while being drawn in and out by a cable reeling system. The piston cutter of the explosive cartridge assembly illustrated in FIG. 12 is of an axial length which results in the blocking off of the elongated slots following detonation. Also, the breech assembly does not include an exhaust port for air positioned in front of the cartridge. Instead, any air that does not escape through the slots prior to passage of the cartridge is compressed in the chamber area forward of the travelling piston cutter.
The prior art explosive charge cable cutting systems suffer from various drawbacks including the failure to efficiently exhaust the gases produced upon detonation of the charge. For example, in some of the prior art embodiments, the resultant gases are exhausted out through the rear of the charge assembly which lowers the driving pressure on the cutter. The prior art also suffers from various problems such as detonation failures, inadequate or incomplete cutting of cables, the unavailability of some of the components for reuse, and difficultly in replacing components.
A failure of the cable cutter assembly to operate can be highly dangerous for pilots involved in aerial gunnery target testing as the pilot is forced to attempt a landing with the target still deployed. Since flight runs are very expensive and there typically is only a limited number of aerial gunnery targets available, it is also important that the aerial gunnery target system and the cable cutter assembly associated therewith be quickly readied for reuse following completion of a flight run. To minimize expense, it is also desirable to reuse as many of the original components of the cable cutter system as possible. The prior art systems are not well adapted for reuse and fast assembly.